Chris' Built-up MEM-Corliss Build

[crueby]

Connecting Rods - Part 3, Finishing Milling

I got out the super-duper expendable non-expensive fixture that I have used to mill con rods on the last several engines - nothing more than a offcut chunk of aluminum bar that I have drilled/threaded for a pair of posts, one at each end of the rod, to hold it securely while milling. As you can see, it has gotten chewed into during milling, that is part of its use, to allow the bottom of the end mill to extend a little past the part without biting into anything desirable, like the chuck or the vise. This time, since the part has a step in it, I milled a groove the depth of the step so the part can sit flat.

With the blank bolted down to the fixture, it was clamped into the 4-jaw on the rotary table, and adjusted until the small end bolt was centered on the rotary table, so that I could mill the round end of the con rod. I started out with a large end mill, and roughed out the shape, leaving a little material before the lines. Photo 1.

Then, switched to a smaller end mill and cut the rounded end on the part. Photo 2.

Then, set the rotary table so that the side of the part was parallel to the mill table, and trimmed off the middle section of the con rod, which is tapered larger a the bottom end and smaller at the top. Photo 3.

Then, done with the fixture, the part was clamped in the mill vise, and the center of the yoke at the small end was milled out to be a slip fit on the fitting at the end of the piston rod. Photo 4.

Last milling step was to cut notches in the base piece to recess the bolts a bit, to give clearance to the base plate under the engine. Photo 5.

After that, a couple swipes on the belt sander to round the end of the base piece, and also the lower end of the yoke, and the parts were done. Photo 6.

Last photo shows one of the con rods set in place to check the fit on the piston rod. I have not bolted in the big end yet, still need to make the bronze bushings there, do that next time...

[10KPete]

Man, that's on honkin' stout rod!! Can't wait to see this whole thing running......

Pete

[Flyboy Jim]

I've enjoyed seeing these Connecting Rods evolve, Chris.

Jim

[crueby]

Man, that's on honkin' stout rod!! Can't wait to see this whole thing running......

Pete

Think it just looks heavy given the small size, the yokes are only 3/32 thick.

Getting close, need bushings, eccentrics and valve chests, and can plumb it for a test run!

[b.lindsey]

I had missed a few posts Chris!  The barring engine is coming along well, but also loved all the pictures from your "fun" weekend as well!!

Bill

[crueby]

I had missed a few posts Chris!  The barring engine is coming along well, but also loved all the pictures from your "fun" weekend as well!!

Bill

Hey Bill! We had a great time that day, and sign of the winter to come, next weekend is our first indoor pool run with the submarines for the year. Summer sure went fast!

[crueby]

All right! The MEM website appears to be back alive again, someone forget to feed the shop gnomes in the server room?

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More work on the connecting rods this weekend. Started by making the big end bearings, used the same split and soldered together chunk of bronze that was used on the crankshaft bearings, was just enough left for these two. As before, drilled the center, turned the outside down, and parted them off. Photo 1.

Then fit/loctited them in place in the con rods. Photo 2.

After test fitting them, and having to mill off a little of the horizontal pieces on the baseplate for clearance, was ready for the bolts to connect to the piston rods. Photo 3.

Started those with some stainless steel hex stock, turned them down to be a slip fit in the yokes, threaded the ends, and parted them off. Also made a couple of nuts to go with them. Photo 4.

Next couple pics show the con rods in place, and everything moving smoothly. 

Then the latest family shot of everything so far, in case you forgot what the Corliss that this barring engine goes with looked like.

Next time, on to the valve chests....

[b.lindsey]

It seems to have been down since yesterday Chris. Glad it didn't keep you out if the shop though. Thanks for another fine update.

Bill

[Flyboy Jim]

Wow............this Barring engine has turned into quite a project in it's own right!

I love the pic of the whole engine package. Also, the Shay in the background. I'm still amazed that you were able to build that with your Sherlines! I can see that I've barely scratched the surface of their capabilities.

Jim

[crueby]

Wow............this Barring engine has turned into quite a project in it's own right!

I love the pic of the whole engine package. Also, the Shay in the background. I'm still amazed that you were able to build that with your Sherlines! I can see that I've barely scratched the surface of their capabilities.

Jim

Thanks! Getting close to having the barring engine going. On the side, I've been looking at the plans, photos, etc for the Lombard Hauling Engine, pretty sure that it will be my next project.  Printed out the side view at a couple of sizes to help decide what scale to make it, large enough to make the tracks easier but small enough to fit on the lathe. Looks like about 1”:1' is the max, comes out to a 30" long model at close to size of the Shay. Neatest thing is it is free running, no rails so can run out in the yard. The tracks will be a challenge, as will the chain drives, those configurations are not available off the shelf in small sizes in metal. There are lots of photos and videos at the Maine logging museum website, should be able to do a really detailed model.
Anyway, still a couple weeks to go on this one first!

[b.lindsey]

The Lombard should be a great project Chris. With your skills it should be a beauty!!

Bill

[crueby]

Moving along to the valve chests - cut and squared up two pieces of flat bar stock, one for the chests, one for the covers. As before, leaving both sets in larger chunks to make holding easier. Started out by clamping the covers and chests together, and drilling for the mounting bolts to hold them to the engine block - this patter matches the one already in the block. Photo 1.

Second photo shows test fit of the first set - all good, so repeated for the other valve chest. Photo 3.

Then, set aside the cover and drilled a starter hole through the center of the chests, and started milling out the space for the valve. Photo 4. Repeated for the other side. Photo 5.

With the milling done, I cut the two sets apart and milled up the cut edge square. Photo 6.

Last photo shows them test fit on the engine, ready to make the valve gland holes and the steam inlet.

[Flyboy Jim]

Boy.............. that bolt pattern must of taken some careful CNC (count number cranks)!

The Lombard Steam Log Hauler looks to be an interesting project............can't wait! Don't think I'd of wanted to be the steerer of that "bad boy"!

Jim

[crueby]

Boy.............. that bolt pattern must of taken some careful CNC (count number cranks)!

The Lombard Steam Log Hauler looks to be an interesting project............can't wait! Don't think I'd of wanted to be the steerer of that "bad boy"!

Jim

The bolts were not too bad, vertically they are all .210 apart, horizontally .100 and .450, so just went up one side and down the other.

Given the Lombard had no brakes, imagine being the front steerer and heading down an incline with hundreds of tons of log sleds behind you, and heading towards a tree... Yikes!

[crueby]

More work on the steam chest yesterday - got the valve packing gland made, which like the piston glands are an o-ring seal held in with a cylinder retainer. No photos of making that, forgot to take any. Whoops! Nothing special about it, just a block with some holes.

After that, I decided to make the steam intake be an internal one rather than running seperate piping to each chest, which makes it simpler to plumb plus easier to take apart the chests for timing the valves. Started by drilling a hole lengthwise through the engine block, just outside the cylinder bores. Photo 1.

Then came back and drilled a passage hole to meet it in the center. Photo 2.

As well as a pair of mounting holes for the pipe flange. Photo 3.

The inlet hole was partly covered by the edge of the steam chest, so milled a recess in the mating face of the chest to give better flow. Photo 4.

And everything re-assembled, photo 5.